Firearm



Dec. 19, 1944. w. 'r. GORTON FIREARM Filed March 10, 1945 Patented Dec. 19, 1944 UNITED STATES PATENT .0FFI CE (Granted under the act of March $1883, as

amended April 30,

The invention described herein may be manufacturecl and used by or for the Government for governmental purposes, without the payment to me or any royalty thereon.

This inventionrelates to improvements in firearms, more particularly to improvements in automatic firearms.

Automatic firearms, particularly. of the blowback type, necessarily require a momentary delay in'the opening of the. action so that the breech pressure will be sufliciently reduced to permit safe opening of the actions Straight blowback type of firearms which employ no special delaying means to retard the opening of the action prior to safe unlocking thereof rely solely on the mass or inertia of the recoiling members for this vitally necessary delay period.

Heretofore firearms of the blowback. type which utilize a cartridge of comparatively high power required a bolt or recoiling member of considerable mass and consequently were of large In order to accommodate such a proportions. large recoiling member the receiver of the firearm had to be of correspondingly large size.. when l such members of the firearm assume large proportions the firearm is exceedingly awkward to handle.

Accordingly it is an object 01 this invention to provide an improved firearm of the blowback type having the mass of the inertia member so distributed as to permit keeping the relative size of the components comparatively small and well balanced.

Another object of this invention is to provide an improved firearm oiv the blowback type hav- Fig. 5 is a side view of the firearm showing an alternate form of stock construction with the stock shown partly in longitudinal section.

The firearm shown in Fig. l in assembled relation comprises mainly a barrel I, a receiver 2 'which is vsecured to the barrel a stock tube 3 which is secured to the receiver 2,. a bolt 4 slidably mounted within the receiver and an inertia member 5 slidably mounted within the stock tube-3.

The receiver 2 and the stock tube 3 may be conveniently made from heavy seamless tubing. The

stock tube 3 is secured as by weldin to the underside of receiver 2 in a rearwardly extending downwardly inclined position as shown in Fig. 1. A longitudinal slot 5, Fig. 2, is provided in the bottom of receiver 2 where tube 3 joins receiver 2 to accommodate one end of inertia member 5 as will be presently described. The barrel l is suitably secured to one end of receiver 2 as by threadsl.

The bolt 4 may be conveniently formed from bar stock and is provided at one endwith an integrally formed'striker point 8. Acentrally located circular recess 9 is provided about the '25 striker point 8 to accommodate the base of a cartridge IL. The and M of bolt 4 is'provided f with a slot I2 to accommodate the end of inertia member 5 as will be described; The bottom [3 of slot I2 is cut at a suitable angle to provide a full bearing for the end otinertia member 5. In

the other end of receiver 2- a plug [5 is secured as by threads to receiver 2. A butler plug it of suitable shock absorbing material may be inserted in an axial hole ll provided in the end or plug it which projects into the interior of receiver-2.

ing a separate inertia member slidably contained within a member constituting the stock of the firearm.

It is a particular object oi this invention to provide an automatic firearm having very few parts of simple design and especially adaptable to quantity production.

. The specific nature or this invention as well as other objects and advantages thereof will clearly appear from a description of apreierred embodiment as shown in the drawing in which: I

The face of plug l8,is perpendicular to the lon itudinal axis of the receiver 2 so that the squared end Ito! bolt 4 will strike solidlyagainst the buii'erplug It at the end of the recoil stroke.

40 The inertia member 5 may also be conveniently end It to pass through the slot 8 in the bottomor receiver 2. The bottom or the flattened por- Fig. 1 is a longitudinal cross sectionalvie w oi thenrearm.

me. 2 at cross sectional view taken sa e plane 2-2 oi P1851.

Fig.3 isa perspective view of the inertia-memhers.

. rig. us an enlargedlongitudinalsectionalview tion of end Ills suitably milled to permit the inertia member to project through and into'the interior'ot the receiver so that the end of the inertia member comes veryclose to the upper.

-inner edge of the receiveras' shownin li'ig. l. The inwardly projecting end otinertia member 5 fully "contacts'thesloped bottom ll of bolt I when the bolt 4 is in battery position; A recoil or' drlving I sprlnl ilis'provided in back! inertia member I mm the cartridge in-the chamber position. as within tube a. l2 be m.

formed from bar stock. The upper end It oi" 'serted in a shallow axial hole 20 in the lower end of inertia member 5. For use with a wooden stock as will be described a plug 2| is preferably secured by threads to the end of tube 3 to retain a butter plug 22 and the driving spring l9 within the tube 3. An axial hole 23 is provided in the buffer plug 22 to receive the compressed driving spring I! when the inertia member is forced rearwardly on the recoil of the recoiling members of the me arm. The buffer plug 22 may also be made of any suitable shock absorbing material.

A preferred form of stock construction is shown in Fig. 3 and comprises a butt plate 31 secured V to the lower end of stock tube 3 and a pistol grip 38. The butt plate 31 is of conventional form point out that in place of the integral striker.

this invention is similar to that of any blowback type of firearm. A loaded magazine 33 is first and is provided with a boss 39 approximately in the center thereof. The boss is preferably secured to the butt plate as by welding and is pro vided with a centrally located hole 40 suitably threaded to accommodate threads 4| provided on the end 42 of stock tube 3 when utilizing this form of construction. The butt plate 31 retains the buffer plug 22 within the tube 3 whenscrewed thereon. It should be understood thatbuifer plug 22 may be made of any suitable length to insure that the forward end of inertia member will always be in contact with the end of bolt 4 regardless of the length of tube 3. The pistol grip 38 is preferably formed from plate stock and is secured in a suitable location on the underside of stock tube 3 as by welding. The pistol grip 38 provides an added measure of support when' firing the firearm.

description that this construction is very rugged It is obvious from the above and strong in addition to being simple and easy to construct.

An alternate form of stock'construction shown in Fig. 1 utilizing a wooden stock 24 may be employed if desired. The wooden stock 24 of conventional configuration is mounted on tube 3. A suitable hole 25 to accommodate tube 3 is provided in stock 24. A boss 26 is welded or otherwise secured near the lower end of tube 3 and is provided with a suitably threaded hole 30 to receive a stock screw 21 for securing stock 24 to tube 3. A suitable slot 28 is provided immediately adjacent the side of hole 25 to pass the boss 28 when the stock is assembled to the tube 3. Stock 'screw 21 is inserted through a suitable hole 29 in stock 24 and into the threaded hole 30 in the boss 26 to secure the stock to tube 3.

A magazine well 3| is secured as by welding to the underside of receiver 2 near the end of barrel I. A suitable opening 32 is provided on the receiver 2 where the magazine well 3| joins receiver 2 to admit a cartridge ll into the receiver. A box magazine 33 of conventional construction may be inserted in magazine well 3| and is secured therein by any conventional means (not shown). Somewhat to the left of magazine well 3! as viewed in Fig. l and on the underside of receiver .2 an opening 34 is provided to admit a sear 35. The sear 35 is connected to any conventional sear mechanism and trigger (not shown). It is also desired to point out that the conventional sear mechanism which may be employed can also be of the semi-automatic or full automatic type or a combination of both so as to enable the gun to be fired semi-automatically or full automatically at will.

. 'A sear notch 36 it provided on the underside of bolt 4 near the end of bolt 4 adjacent barrel I.

An extractor (not shown) and an ejector (also not shown) of any conventional form may be provided on bolt 4 if desired. It is desired to is chambered in th barrel l.

inserted in magazine well 3|. The operating han-' pushed or cammed downwardly by the sloped surface l3 on the rear end of bolt 4. As the inertia member is cammed downwardly driving spring is is compressed. When bolt 4 has been withdrawn rearwardly a sufficient distance sear 35 will engage sear notch 36 and will retain bolt 4 and inertia member 5 in the recoiled position. The firearm is now ready to be fired. When the sear 35 is disengaged from sear 36 by the trigger (not shown) spring l9 biases inertia member 5 forwardly and as the inertia member 5 remains in contact with bolt 4 at all times forces the bolt 4 forwardly until it strikes the base of cartridge l l. The cartridge l I is forced out of magazine 33 and Simultaneously striker point 8 strikes the primer of the cartridge thereby discharging cartridge I I. The opening of bolt 4 is delayed for a suilicient length of time by the mass of the bolt 4 and the inertia member be made somewhat smaller in mass than would be required for a conventional blowback firearm hence permitting the use of still smaller components and effecting a further saving in weight. When the force of the explosion of cartridge H overcomes the inertia of bolt 4 and inertia member 5 these members will be driven rearwardly until bolt 4 contacts buffer plug I6 and inertia member 5 contacts buffer plug 22. If the trigger mechanism (not shown) is set for semi-automatic fire, sear 35 will again engage sear notch 38 and hold bolt and inertia member in the recoiled position until such time as the trigger is again released.

It is evident that the size of inertia member 5 and bolt 4 may be readily varied to accommodate cartridges of greater or less power. The preferred proportioning distributes a large proportion of'the recoiling mass in the inertia member and hence results in a'bolt of small proportions. It is readily apparent that if the bolt 4 itself had sufllcient massto delay theopening of the action slightly the size of the bolt 4 and hence of receiver 2 would have to assume greatly increased proportions which would make for a bulky and somewhat difiicult firearm to handle. With the construction disclosed in this description it is obvious that the size of receiver 2 is comparatively small and that the firearm presents a compact appearance and may be readily. conveniently and quickly handled. By providing a separate inertia .member 5 a'large proportion 01 the mass necessary in a blowback type of firearm may thus be disposed within the stock of the firearm in the manner above described.

I claim: I

1.- In a firearm, a receiver, a bolt arranged to reciprocate in said receiver between battery and ment, the rear end of said bolt being bifurcated.

recoil positions, an inertia member mounted for reciprocating movement with respect to said receiver along a path angularly disposed with respectto the path of movement of said bolt, resilient means biasing said inertia member forwardly into engagement with said bolt, the rear end of said bolt being bifurcated, the forward end' of said inertia member being shaped to be engageable in the bifurcated end of the bolt in all positions of said bolt, said bolt and inertia member having a combined mass suflicient to delay movement of the bolt from battery position upon firing of a cartridge until the developed gas pressure is reduced to a safe value, said inertia member comprising the major portion of said mass.

2. In a firearm, a receiver, a bolt arranged to reciprocate in said receiver between battery and recoil positions, a shoulder stock including a tubular member secured to the rear of said receiver, the axis of said tubular member being angularly disposed with respect to the path of movement of said bolt, a cylindrical inertia member mounted in said tubular member for reciprocating movethe end of said inertia member adjacent said bolt being shaped to be engageable in the bifurcated end of said bolt in all positions of said bolt, and a spring mounted in said tubular member biasing said inertia member into engagement with said bol 3. In a firearm, a receiver, a bolt arranged to reciprocate in said receiver between battery and recoil positions, a shoulder stock including a tubular member secured to the rear of said receiver, the axis of said tubular member being angularly disposed with respect to the path of movement, of

said bolt, a-cylindrical inertia member mounted in said tubular member for reciprocating movement, the rear end of said bolt being bifurcated, the end of said inertia member adjacent said bolt being shaped to be engageable in the bifurcated end of said bolt in all positions of said bolt, a spring mounted in said tubular member biasing said inertia member into engagement with said bolt, said bolt and inertia member having a combined mass sufficient to delay m'ovementof the bolt from battery position upon firing of a cartridge until the developed gas pressure is reduced to a safe value, said inertia member comprising the major portion of said mass.

WALTER T. GORTON. 

